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Port write-region-inhibit-sync, allowing avoidance of bad FS performance. See http://shaver.off.net/diary/2008/05/25/fsyncers-and-curveballs/ for more details. 2008-08-09 Aidan Kehoe <kehoea@parhasard.net> Integrate Romain Francoise' 2005-09-14 (pre-GPLV3) GNU change, which can allow much better performace with some stupid filesystems: * fileio.c (write_region_inhibit_fsync): New variable. (Fwrite_region): Use it to skip call to fsync. (syms_of_fileio): Initialize it.
author Aidan Kehoe <kehoea@parhasard.net>
date Sat, 09 Aug 2008 16:44:46 +0200
parents 732b87cfabf2
children a5210e70ffbe
comparison
equal deleted inserted replaced
4493:89406c31b125 4499:eb82259f265d
108 int inhibit_auto_save_session; 108 int inhibit_auto_save_session;
109 109
110 int disable_auto_save_when_buffer_shrinks; 110 int disable_auto_save_when_buffer_shrinks;
111 111
112 Lisp_Object Vdirectory_sep_char; 112 Lisp_Object Vdirectory_sep_char;
113
114 #ifdef HAVE_FSYNC
115 /* Nonzero means skip the call to fsync in Fwrite-region. */
116 int write_region_inhibit_fsync;
117 #endif
113 118
114 /* These variables describe handlers that have "already" had a chance 119 /* These variables describe handlers that have "already" had a chance
115 to handle the current operation. 120 to handle the current operation.
116 121
117 Vinhibit_file_name_handlers is a list of file name handlers. 122 Vinhibit_file_name_handlers is a list of file name handlers.
3566 #ifdef HAVE_FSYNC 3571 #ifdef HAVE_FSYNC
3567 /* Note fsync appears to change the modtime on BSD4.2 (both vax and sun). 3572 /* Note fsync appears to change the modtime on BSD4.2 (both vax and sun).
3568 Disk full in NFS may be reported here. */ 3573 Disk full in NFS may be reported here. */
3569 /* mib says that closing the file will try to write as fast as NFS can do 3574 /* mib says that closing the file will try to write as fast as NFS can do
3570 it, and that means the fsync here is not crucial for autosave files. */ 3575 it, and that means the fsync here is not crucial for autosave files. */
3571 if (!auto_saving && fsync (desc) < 0 3576 if (!auto_saving && !write_region_inhibit_fsync && fsync (desc) < 0
3572 /* If fsync fails with EINTR, don't treat that as serious. */ 3577 /* If fsync fails with EINTR, don't treat that as serious. */
3573 && errno != EINTR) 3578 && errno != EINTR)
3574 { 3579 {
3575 failure = 1; 3580 failure = 1;
3576 save_errno = errno; 3581 save_errno = errno;
4558 DEFVAR_LISP ("auto-save-list-file-name", &Vauto_save_list_file_name /* 4563 DEFVAR_LISP ("auto-save-list-file-name", &Vauto_save_list_file_name /*
4559 File name in which we write a list of all auto save file names. 4564 File name in which we write a list of all auto save file names.
4560 */ ); 4565 */ );
4561 Vauto_save_list_file_name = Qnil; 4566 Vauto_save_list_file_name = Qnil;
4562 4567
4568 #ifdef HAVE_FSYNC
4569 DEFVAR_BOOL ("write-region-inhibit-fsync", &write_region_inhibit_fsync /*
4570 *Non-nil means don't call fsync in `write-region'.
4571 This variable affects calls to `write-region' as well as save commands.
4572 A non-nil value may result in data loss!
4573 */ );
4574 write_region_inhibit_fsync = 0;
4575 #endif
4576
4563 DEFVAR_LISP ("auto-save-list-file-prefix", &Vauto_save_list_file_prefix /* 4577 DEFVAR_LISP ("auto-save-list-file-prefix", &Vauto_save_list_file_prefix /*
4564 Prefix for generating auto-save-list-file-name. 4578 Prefix for generating auto-save-list-file-name.
4565 Emacs's pid and the system name will be appended to 4579 Emacs's pid and the system name will be appended to
4566 this prefix to create a unique file name. 4580 this prefix to create a unique file name.
4567 */ ); 4581 */ );